Help again,
May we please have some details?
(1) How are are connecting to the internet and to WordPress.com. The way you connect to the internet (mobile, satellite, DSL, dial-up) and to your blog, and how many proxy server jumps etc. it takes to connect can cause problems. There maybe be problems with your ISP and/or with the proxy servers. Also note that the main dashboard isn’t designed to work with touch devices through the tablet and smartphone browsers.

Hello, Timethief.
1) I connect to the internet by DSL; I don´t understand the second part of this question ("how many proxy server jumps...")
2) I tried to edit my post first in Google Chrome, and then with Mozilla Firefox. In both cases (last versions) the result was the same.
Thank you very much!